name: Screensaver Event Trigger Execution
id: 58cea3ec-1f6d-11ec-8560-acde48001122
version: 1
date: '2021-09-27'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: This analytic is developed to detect possible event trigger execution
  through screensaver registry entry modification for persistence or privilege escalation.
  This technique was seen in several APT and malware where they put the malicious
  payload path to the SCRNSAVE.EXE registry key to redirect the execution to their
  malicious payload path. This TTP is a good indicator that some attacker may modify
  this entry for their persistence and privilege escalation.
data_source:
- Sysmon Event ID 13
search:
  selection1:
    TargetObject: '*\\Control Panel\\Desktop\\SCRNSAVE.EXE*'
  condition: (selection1)
how_to_implement: To successfully implement this search, you must be ingesting data
  that records registry activity from your hosts to populate the endpoint data model
  in the registry node. This is typically populated via endpoint detection-and-response
  product, such as Carbon Black or endpoint data sources, such as Sysmon. The data
  used for this search is typically generated via logs that report reads and writes
  to the registry.
known_false_positives: unknown
references:
- https://attack.mitre.org/techniques/T1546/002/
- https://dmcxblue.gitbook.io/red-team-notes-2-0/red-team-techniques/privilege-escalation/untitled-3/screensaver
tags:
  analytic_story:
  - Windows Persistence Techniques
  - Windows Privilege Escalation
  - Windows Registry Abuse
  - Hermetic Wiper
  asset_type: Endpoint
  confidence: 90
  impact: 80
  message: modified/added/deleted registry entry $Registry.registry_path$ in $dest$
  mitre_attack_id:
  - T1546
  - T1546.002
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: user
    type: User
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  risk_score: 72
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1546.002/scrnsave_reg/sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog